A data center houses computer systems and associated components, such as servers, storage systems, and virtual computing resources. Communications in data centers are commonly based on networks running the IP protocol suite. Data centers typically contain a set of routers and switches that transport traffic between the servers and to the Internet. Some of the servers at the data center are used for running the basic Internet and intranet services needed by internal users in the organization, e.g., email servers, proxy servers, and DNS servers. Some data centers utilize virtualization in a hosting environment scenario to provide increased services to customers.
A virtual machine (VM) simulates the hardware resources of a physical server. Multiple VMs, each with their own native operating system (OS), can securely run on a single physical server. Hosting VMs in a data center helps bridge the gap between shared web hosting services and dedicated hosting services: this allows one customer's VM to have more independence from other customers' VM implementations, and it costs less than it does to operate dedicated physical servers.
A guest VM operates logically on top of a hypervisor within a physical host system. The hypervisor is a software layer that typically provides virtualization, e.g., virtual versions of computing resources such as physical processors, memory, and peripheral devices. In certain embodiments, the hypervisor may execute on top of a host operating system; in others, it may execute directly (logically) on top of the host hardware (“bare-metal hypervisors”).
A storage area network (SAN) is a dedicated network of devices that provide access to consolidated, block-level data storage. SANs are primarily used to enhance storage devices, such as disk arrays, tape libraries, and optical jukeboxes, that are accessible to servers so that the devices appear to be devices locally attached to the operating system. A storage device is commonly associated with how many Input/Output Operations Per Second (IOPS) it can perform for facilitating storage operations from clients (e.g., physical and/or virtual devices).